Indian authorities have detained four high school students suspected for raping a younger girl, after a video clip circulated on WhatsApp messaging system.

The gang rape occurred on November 8 in a high school in Mumbai and came to the attention of police Thursday, when the girl’s aunt informed them.

The 15-year-old victim had kept quiet about the assault because her attackers threatened her with reprisals. But she gave a full account of the story after her aunt saw the video that allegedly was posted by her attackers.

The four suspects are 16 and 17 years old. According to a senior police official, they have confessed and were sent to the Dongri correction home, a juvenile detention facility in India's commercial capital, Mumbai.

India has had a long history of tolerance of sexual violence, but a fatal gang rape of a 23-year-old woman on board a bus in New Delhi in December 2012 caused outrage across the nation.

The federal government was forced to quickly pass legislation doubling prison terms for rapists to 20 years. The law also makes it a crime for officers to refuse to open cases when complaints are made.

There has been a fierce debate in recent days on the issue of how India should treat minors accused of sexual offenses ahead of the imminent release of the teenager convicted of the gang-rape on board the bus in New Delhi.